package com.example.iis.util;


import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * @author: Farben
 *
 * @description: AESUtil-cryp加密解密类
 *
 * @create: 2019/8/21-10:17
 **/
public class AESUtil {
 
    /**
     * 加密
     *
     * @param content 需要加密的内容
     * @param password  加密密码
     * @return
     */
    public static byte[] encrypt(String content, String password) {
        try {
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(password.getBytes());
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128, secureRandom);
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            byte[] byteContent = content.getBytes("utf-8");
            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(byteContent);
            return result; // 加密
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }
        return null;
    }
 
 
 
    /**解密
     * @param content  待解密内容
     * @param password 解密密钥
     * @return
     */
    public static byte[] decrypt(byte[] content, String password) {
        try {
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(password.getBytes());
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
                kgen.init(128, secureRandom);
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(content);
            return result; // 加密
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }
        return null;
    }
 
 
 
    /**将二进制转换成16进制
     * @param buf
     * @return
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }
    /**将16进制转换为二进制
     * @param hexStr
     * @return
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length()/2];
        for (int i = 0;i< hexStr.length()/2; i++) {
            int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
            int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }


//    public static void main(String[] args) {
//        /**
//         * 第一种
//         */
//        String content = "iisuser";
//        String password = "iisuser_db_key";//解密私钥
//        //加密
//        System.out.println("加密前：" + content);
//        byte[] encryptResult = AESUtil.encrypt(content, password);
//        String encryptResultStr = AESUtil.parseByte2HexStr(encryptResult);
//        System.out.println("加密后：" + encryptResultStr);
//        //解密
//        byte[] decryptFrom = AESUtil.parseHexStr2Byte(encryptResultStr);
//        byte[] decryptResult = AESUtil.decrypt(decryptFrom, password);
//        System.out.println("解密后：" + new String(decryptResult));
//
//    }
}
